Surface tagging system with wired tubulars

ABSTRACT

Downhole systems and methods including tags configured to provide distinguishable identifiers are set for selective release to a subsurface location. Sources/sensors in the wellbore are activated to detect the tags at a subsurface location, and signal data associated with the detected tags is conveyed to the surface.

BACKGROUND

1. Technical Field

The present invention relates generally to the field of subsurfacemonitoring and communication techniques. More specifically, theinvention relates to the use of tracers or marker materials incombination with wired tubulars for subsurface measurements.

2. Description of Related Art

Drilling operations in the oil and gas industry typically entail thecirculation of a drilling fluid (“mud”) down the drill string, throughthe drill bit and up along the annulus to surface. The drilling mud hasvarious functions including cooling, cleaning and lubricating the drillbit and bottom-hole assembly; controlling subsurface pressures to givewellbore stability and prevent fluid influxes, and transporting drillcuttings to the surface where they can be separated and disposed of.

Downhole pressure control is a primary function of the drilling mud.Maintaining hydrostatic pressure to prevent fluid influxes which maylead to kicks and a well control situation is crucial. However, thecirculating pressure must be controlled to be below the fracturepressure for the formation otherwise fractures can propagate causingloss of drilling fluid from the wellbore. In extreme cases this couldcause loss of hydrostatic pressure in part of the annulus where a fluidinflux could occur. Various techniques have been considered to monitorflow rates.

Efficient cuttings transport is another key function of the drillingmud. The rheological properties of the mud are engineered to suspend andlift the cuttings in the circulating fluid. However, the conditions inthe annulus, particularly diameter and inclination, can affect flowrates, and lessen transport efficiency. In horizontal and deviatedwells, where flow rates may be insufficient to keep cuttings insuspension, cuttings beds can build up on the bottom side of the hole.This is a particular problem in high angle holes where the cuttings bedmay slump down the annulus and packoff the drill string causing pipesticking, twist offs and potentially lost circulation if a weakformation lies below the obstruction in the annulus. Wellbore washoutscan lead to areas of significantly enlarged wellbore diameter,dramatically lowering flow rates which can drop cuttings out ofsuspension in the fluid. Washout, zones are zones of high formationerosion which can be indicative of, or cause wellbore stability problemsand can lead to further problems in efficiently cementing the well.Early detection of trouble zones and timely intervention could preventcostly operational problems

Conventional “mud-logging” techniques include monitoring the mud weightat surface as it enters and exits the well and computation of thecuttings load versus the expected load from the rate of cuttingsgeneration. A drawback of these techniques is the inaccuracy due to themethods of mud weight measurement. The wellbore, as drilling continues,is a very dynamic environment and through different processes the fluidflow can often be disrupted, making mudlog determinations subject toinaccuracies. Attempts to evaluate changes in the time it takes cuttingsto reach surface (“lag time”) have been crude and basic.

Tracers have been used in the oil and gas industry for many years. Oneconventional technique has been to use radioactive substances astracers. U.S. Pat. No. 5,243,190 describes the use of radioactiveparticles for subsurface tracers. A conventional technique fordetermining lag time entails the injection of Calcium Carbide pellets,enclosed in a water-proof container, at the surface of the well beingdrilled for transit down the borehole by the mud stream. When passingthrough the drill bit, the container is smashed releasing the calciumcarbide that reacts with water in the mud to form a gas. Acetylene,which is detected at the surface with a gas analyzer. The lag time cantherefore be determined from the time difference between the injectionof the Calcium Carbide in the well and the detection of gas at thesurface in the return mud. The addition of rice to the mud stream hasalso been used as a tracking technique to determine lag time.

Various chemicals have been used as tracers in subsurface applications.For example, U.S. Pat. No. 4,447,340 describes a method of tracingdrilling mud by determining the concentration of Acetate tracer ion inthe penetrated strata (by core analysis). The use as tracers ofDichromate, Chromate, Nitrate, Ammonium, Cobalt, Nickel, Manganese,Vanadium and Lithium is also mentioned. Some tracer techniques have alsobeen proposed using spectroscopic techniques, including atomicabsorption spectroscopy. X-ray fluorescence spectroscopy, or neutronactivation analysis, to identify certain materials as tagging agents.U.S. Pat. No. 6,725,926 proposes the use of a proppant coated withphosphorescent, fluorescent, or photoluminescent pigments that glow inthe dark upon exposure to certain lighting Fluorescence spectrometrytechniques entailing the illumination of fluids with a light source havealso been proposed (See U.S. Pat. Nos. 7,084,392, 6,707,556, 6,564,866,6,955,217).

A need remains for improved techniques to determine dynamic subsurfaceconditions, particularly in the field of oil, gas, or water explorationand production.

SUMMARY

One aspect of the invention relates to a downhole system that includesat least one tag configured to provide a distinguishable identifier andset for selective release to a subsurface location and at least onesensor disposed in the borehole to detect the at least one tag at asubsurface location. The at least one sensor may be configured totransmit a signal associated with the at least one detected tag asurface.

Another aspect of the invention relates to a method that includesdetecting at least one tag at a subsurface location with a sensordisposed in the borehole, the tag configured to provide adistinguishable identifier and conveying a signal associated with the atleast one detected tag to a surface location.

Another aspect of the invention relates to a downhole method thatincludes activating at least one source or sensor disposed in theborehole to detect a tag at a subsurface location, the tag configured toprovide a distinguishable identifier and conveying a signal associatedwith the detected tag along an interconnected wired tubular.

BRIEF DESCRIPTION OF THE DRAWINGS

Other aspects and advantages of the invention will become apparent uponreading the following detailed description and upon reference to thedrawings in which like elements have been given like numerals andwherein:

FIG. 1 is a schematic of an example downhole system including tagrelease units and a tag detection unit.

FIG. 2 is a schematic of an example tag release unit.

FIG. 3 is a schematic of an example downhole system including tagactivation/detection units.

FIG. 4 is a flow chart of an example downhole method for detecting oneor more tags.

FIG. 5 is a flow chart of an example downhole method for activating oneor more tags.

DETAILED DESCRIPTION

Disclosed examples entail the use of wired tubulars configured fordownhole applications. Such tubulars are configured with one or moreconductors running through the bore, or disposed within/against/outsidethe wall, of the tubular. Couplers mounted on the ends of the tubularsallow for conveyance of a signal/power along a string of interconnectedtubulars. Wired drill pipe is one such type of tubular. Conventionalwired drill pipe configurations that may be used to implement aspects ofthe invention are described in U.S. Pat. Nos. 7,168,510, 6,950,034,6,641,434, 6,866,306, 7,040,415, 7,096,961, U.S. Patent Publication Nos.20070063865, 20070159351, 20070188344, and 20060225926 (all documentsincorporated herein by reference in their entirety).

FIG. 1 shows an aspect of the invention. A system 11 includes a drillstring 20 comprising a plurality of interconnected wired drill pipes 21,shown disposed within a borehole 22 traversing a subsurface formation Fas the hole is cut by the action of the drill bit 24 mounted at the farend of a bottom-hole assembly (BHA) 26. BHA 26 contains a number ofdevices including various subassemblies 28, including those used formeasurement-while-drilling (MWD) and/or logging-while-drilling (LWD).Signal data between the subassemblies 28 and the surface is communicatedvia the interconnected wired drill pipes 21 as known in the art. In someaspects of the invention, the signal data may be conveyed via a seriesof wired drill pipes 21 in combination with another telemetry assembly(e.g., via pressure pulses through the drilling mud, via a wirelinecable in the drill string) (not shown) as known in the art.

At the surface, the system 11 includes a derrick 30 and hoisting system,a rotating system, and a mud circulation system. Although this aspect ofthe invention is shown in FIG. 1 as being on land, those skilled in theart will recognize that, the present invention is equally applicable tomarine or offshore environments. A mud circulation system pumps drillingfluid down the central opening in the drill string 20. The mud is storedin a mud pit which is part of a mud separation and storing system 32.The mud is drawn in to mud pumps (not shown) which pump the mud throughstand pipe 34 and into the Kelly and through the swivel,

The mud passes through drill string 20 and through drill bit 24. As thedrill bit grinds the formation into cuttings, the mud is ejected out ofopenings or nozzles in the bit. These jets of mud lift the cuttings offthe bottom of the hole and away from the bit, and up towards the surfacein the annular space between drill string 20 and the wall of theborehole 22, as represented by arrows in FIG. 1. At the surface the mudand cuttings leave the well through a side outlet in a blowout preventer36 and through a mud return line 38. The mud return line 38 feeds themud into the separation and storing system 32, which separates the mudfrom the cuttings. From the separator, the mud is returned to a mud pit(not shown) for storage and re-use.

As shown in FIG. 1, some examples entail the use of tags 10 to tracefluids and solids in a subsurface environment and to provide means ofcommunication and monitoring. For purposes of this disclosure, the term“tag” is understood to comprise any conventional tracer/marker elementor composition configured to provide a distinguishable identifier asknown in the art. Such tags 10 are generally miniature in size andconfigured in various shapes and dimensions (e.g., a ball, bead, rod,ribbon, sphere, globule, droplet, tube). Similarly, the term“subsurface” is herein understood as, relating to, or situated in anarea beneath a surface, especially the surface of the earth or of a bodyof water. For example, a subsurface component is understood to comprisea buried, submerged, or partially buried/submerged component Accordingto some aspects of the invention, tags 10 are disposed in the mudseparation and storing system 32, such that they are set for selectiverelease to a subsurface location via the mud flow.

A tag 10 detection unit 40 is shown coupled into the mud return line 38and linked to surface equipment 42 comprising computer, display,recording, and user interface means as known in the art. In some aspectsof the invention, the detection unit 40 includes appropriate componentsto activate/detect, the passing tags 10 in order to resolvable/identifythe individual tags. For example, when fluorescence emitting tags 10 areused, a radiation source (e.g., UV lamp) and optics to provideappropriate wavelength illumination may be included in the detectionunit 40. An aspect can be implemented wherein the detection unit 40 isincorporated with a filtering or separating device, such as acentrifuge, to collect the tags 10 for analysis. In aspects wherein thetags 10 comprise a ferromagnetic material, the detection unit 40 can beimplemented with magnetic means (e.g., permanent magnet orelectromagnet) to collect the particles for processing (not shown).

In other examples, a system can be implemented wherein the tags 10 areset in a release mechanism disposed on the BHA 26, or anywhere along thedrill string 20, such that they are selectively or automaticallyreleased subsurface at a desired depth or when a predetermined eventoccurs, or at specified times. Tagging of solids and fluids downholegives a more precise to time event for both. FIG. 1 illustrates such anaspect of the invention. The BHA 26 may be implemented with a toolcomprising a tag 10 release unit 44.

Turning to FIG. 2, an example of a tag 10 release unit 44 is shown. Inone example, a tag release unit 44 may be implemented with a sensor 46adapted to sense a subsurface characteristic or condition (e.g.,pressure, temperature, fluid composition, flow rates, etc). Sensors ofthese types are well known technology, as are the means to power thesensors. Sensor 46 is in communication with a processor 48 which maycomprise a number of microprocessors. One or more chambers 50, 52contain the tags 10. Aspects can he implemented with different types oftags 10 (e.g., various sizes, activation modes, liquid type, solid type,etc.) disposed in each chamber 50, 52 for selective release of thedesired tag(s) at the desired times.

Associated with the chambers 50, 52 are release mechanisms 54, 56. Undercontrol of processor 48, the release mechanisms 54, 56 can be activatedto selectively release the respective tag(s) 10. The release mechanisms54, 56 may be configured to release the tag(s) 10 via a forced orpressurized ejection (e.g., pneumatic, hydraulic, electronic, mechanicalmeans), via direct exposure of the tags to the mud flow, or somecombination of these methods as known in the art. In some aspects, therelease mechanisms 54, 56 may be instructed to release the tags 10 inaccordance with a program in the processor 48. In this manner, therelease mechanisms 54, 56 can be instructed to selectively release theirtags 10 when different predetermined thresholds or conditions aredetermined by the sensor 46, based on input from other sensors in thesystem, or via direct control from, a surface operator/computer withsignaling conveyed along the wired drill pipes 21. The use ofinterconnected wired tubulars in aspects of the invention allows forreal-time signal/data transfer and correlation to depth/rime ofsubsurface tag 10 release and/or detection.

The wired drill pipes 21 are also equipped with conventionalsources/sensors 60 configured to activate and/or detect tags 10 in theirvicinity as known in the art and disclosed herein. For example, U.S.Patent Publication No. 20060260801 to Hall describes wired drill pipesequipped with sensors and power sources to obtain subsurfacemeasurements. In aspects wherein electromagnetic (EM) energy is thedesired mode to activate/detect the tags 10, conventional LWD antennaconfigurations may be used. U.S. Pat. No. 6,577,244 (assigned to thepresent assignee and entirely incorporated herein by reference)describes a drill pipe system providing various types of sources/sensorsfor subsurface measurements. As discussed above, aspects of theinvention may be configured with “hybrid” telemetry systemsincorporating the wired drill pipes 21 in combination with drill pipesystems such as described in U.S. Pat. No. 6,577,244.

FIG. 3 shows another example of a tagging system. A system 70 is showndisposed within a cased well 51. The well 51 is configured withconventional tubing/liners/casing 53 as known in the art. A drill string20 comprising a plurality of interconnected wired drill pipes 21 isdisposed within the well 51. The wired drill pipes 21 are equipped withconventional sources/sensors 60 configured to activate and/or detecttags 10 in their vicinity as known in the art. In this example, one canperform status/performance checks such as identifying the position ofcement 57 behind casing by detection of tags 10 that have been added tothe cement. The system 70 may also be used to provide positivecommunication to the surface regarding a specific subsurface condition,such as confirmation that gravel packing (incorporating tags 10) wasproperly placed or distributed in the well (not shown). Such functionscan be performed while tripping the drill string 20 in or out of thewell 51. As with the other aspects of the invention, this system mayalso be configured for selective release of the particles 10 from thesurface and/or the BRA as disclosed herein.

As previously discussed, example systems may be implemented with tags 10comprising any conventional tracer/marker material or compositionconfigured to provide a distinguishable identifier as known in the art.For example, aspects of the invention can be configured to detect tags10 exhibiting fluorescence emission. Instruments configured to detectfluorescence emission downhole are known in the art. U.S. Pat. No.6,704,109 (incorporated herein by reference in its entirety) describes afool equipped with a probe system to illuminate crude oil in the welland defect the emitted fluorescence. Examples may be implemented withsimilar optical systems such that the tags 10 can be released,irradiated, and observed subsurface. In one example, the sources/sensors60 on the drill string 20 of FIG. 1 can comprise fluorescence detectorunits mounted at longitudinally-spaced intervals. Such embodiments canbe used to detect the tags 10 subsurface and provide the data, tosurface instrumentation 42 whenever there is tag movement near adetector. Alternatively, one or more drill pipes 21 may be equipped witha source/sensor 60 comprising a fluorescence detector unit configured toilluminate and detect tags 10 previously released or affixed to theborehole/casing wall, such as tags disposed in proppant/fracturingcompounds and stuck in fissures or mudcake.

The distribution of sources/sensors 60 along the drill string 20 permitsspatial resolution to obtain measurements and track fluid/cuttings flowwhile drilling. In some examples, the surface equipment 42, alone or incombination with processors in the downhole tool(s), can be programmedto automatically alter operation of surface and subsurface componentsbased on the tag-related measurements obtained subsurface and/or atsurface. Such a feedback/control loop can be configured to affect,operations to alter pump rates, torque, ROP, pipe rotation, trippingrates, activate/deactivate instruments, etc. For example, on detectionof a cuttings bed a command could be sent to increase rotation rate andactivate the sensors to monitor the cuttings bed pickup. Such controlscan be maintained to correct or stabilize downhole conditions.

Selective release of the tags 10 and controlled activation of thesources/sensors 60 provides a means to track and monitor transit.Detection of cuttings hold-ups in washouts and beds along the annuluscan be achieved by measuring the time of flight and comparing thetransit of the cuttings with that of the drilling mud. In one aspect,the tags 10 can be activated/released to tag the drilling mud andcuttings at the BHA 26. These tags 10 travel up the annulus andexperience hydrodynamical dispersion and convectional and diffusionalmixing effects. On detection of the tags 10 at the sensors 60 along thewellbore and/or at surface 40, the difference in time of flight can becalculated. Where the two deviated significantly, a zone of cuttingshold-up can be identified.

The tag(s) 10 can be automatically or manually released into the annulusfrom the surface, at the bit 24, or near the bit at the BHA 26, withdata transmitted near instantly along the wired drill pipe 21 system. Inanother aspect, measurement of dispersion and transit of the drillingmud can be done through soluble ions, as described in U.S. Pat. No.4,807,469 (assigned to the present assignee and entirely incorporatedherein by reference). Sensors 60 comprising conductivity or ion-specificsensors on the drill string 20 are used to detect the passage of tons.Other examples use tags 10 comprising dyes which are detectable atspecific wavelengths or fluorescence used in conjunction with sensors 60comprising optical sensors. Tags 10 exhibiting other spikes in chemicalcomposition such as pH may also be used provided that the otherproperties of the fluid remain unaffected. Solid transit could be doneby dosing the mud with a tag 10 comprising a weighting agent (e.g., NORMBarite or other detectable solids added at the surface or the BHA).Brazil nut shells, for example, provide significant natural radiationand are available as loss prevention materials.

Electronic tags 10 such as encapsulated radio-frequency identification(RFID) tags may also be used. RFID tags are configured foractivation/interrogation by EM energy and have been proposed for use insubsurface applications. U.S. Pat. No. 6,993,432 (incorporated herein byreference in its entirety) describes the use of RFID tags forcommunication means in a wellbore. Examples may be implemented withconventional EM sources/sensors 60 (e.g., as described in U.S. Pat. No.6,577,244) configured to detect/interrogate such tags 10 subsurface. Insome examples, the tags 10 can be used in a circulating sweep. Pills ofmore viscous fluid are often deployed to displace cutting which havebecome help-up. The arrival of the sweep and its effectiveness could bemonitored. The feedback/control loop of the disclosed systems can beused to alter components and parameters timed to the arrival of thesweep.

Processing of detected tags 10 can be carried out using conventionaltechniques. For example, upon identification of a tag 10, thedistinguishable tag identifier can be matched against a referencedatabase or “code chart.” It will be appreciated by those skilled in theart that any suitable tags 10 and corresponding sources/sensors 46 maybe used to implement embodiments of the invention. The detection andidentification of the tags 10 can be assisted by the use of a camerathat can be used to record images or display on a screen. An aspect ofthe detection unit 40 of FIG. 1 may comprise a conventional cameraconfigured to record and display images on a screen. The surfaceequipment 42 may also be configured with a program to identify the tags,establish tag identifier matching, process the resolved/identified tagdata, track tag travel times, automatically trigger selected tagrelease, and respectively transmit/receive data/commands to/from remotelocations. In aspects comprising tag imaging, the surface equipment 42may be configured with programming to perform image analysis for tagidentification. In some aspects, a simplistic system can be implementedwherein the tags 10 are initially disposed in the mud manually andcaptured in the return line 38 (e.g., using a screening filter, magnetmeans, centrifuge or separator) for processing by rig personnel.

The disclosed aspects of the invention offer a variety of applicationsfor the wired tubular and tag systems. In addition to, and/or furtherelaborating on, the previously disclosed applications, uses of thedisclosed embodiments for subsurface applications include, but are notlimited to:

Mud logging—The use of uniquely identifiable tags added to the drillingmud at different times provides different types of information:

Circulation time at specific time slots. The travel time of differenttags can be logged. The time between the release and the detection ofthe tags can be measured, as well as the travel time between two or moreestablished locations.

Cuttings monitoring—Timed tag release allows for direct cuttingstransport, rate measurements for hole-cleaning calculations, deductionof hole volume/gauge via annular velocity measurement with a known flowrate, identification of “thief zones” at times of lostcirculation/signal.

Mud loss detection. A dip of the concentration of a given tag in the mudto indicate greater loss of drilling fluid at a particular depth.

Kick location. A surge of the concentration of a given tag in the mud toindicate that that zone is starting to produce.

Mud cake formation estimation.

Rheological modeling.

Mud cake tagging—The use of uniquely identifiable tags added to thedrilling mud at different times can tag the mud cake as a function ofdepth that is correlated with the drilling depth. This provides for:

Correlating drilling depth and wireline depth. This may be done bysampling the mud cake at certain depths.

Cement placement identification. Via analysis of the displaced mud ortag location detection.

Clean up treatment monitoring. The amount and type of debris may beestimated using the tags.

Cement analysis—Addition of tags to cement allows the position of cementbehind casing to be identified while tripping past with the wired drillpipe, or recordation in combination with sensors disposed in the casing,liner or any other tubular in or outside of the borehole.

Drill bit communication—In cases where mud pulse telemetry cannot beused, a tag release unit can selectively release a combination of tagsinto the mud to convey information from the drill bit to surface.

Gravel pack monitoring—Different types of tags can be added to thegravel at different times during the gravel packing operation. Theeffectiveness of the placement at different stages of the operation canbe monitored by analyzing the concentration of the different tagsdetected by the passing wired tubulars. This can be used to identifywhich region of a gravel pack has failed, for example.

Flow measurement—The release of tags into the mud flow can be used toobtain flow velocity. In such aspects, the tags' surface can be treatedas known in the art to increase their affinity to a given fluid whenmulti-phase flows are measured. Monitoring of circulated “pills” and“sweeps” or other wellbore treatments.

General testing—Tags can be sent from the surface or selectivelyreleased subsurface to test the operation of downhole instruments or todetermine/monitor downhole conditions. Tags can be added to the mud,cement, acid, injection fluid, produced fluid, fracturing fluid,proppant, treatment fluid, gravel, etc. The location of an event can bedetermined by the type and concentration of tags detected. Different tagsizes can be used in combination to perform any of the operationsdisclosed herein. For example, the use of different sized tags allowsfor determination of the size of a fracture, fault, porous medium, etc.,that serves as a conduit to the fluids or tags. The tags can also bemixed with solid acids or other compounds to track/monitor completionoperations.

FIG. 4 shows a flow chart of an example downhole method 100 thatincludes, at step 105 disposing a plurality of interconnected wiredtubulars 21 within a borehole traversing a subsurface formation. At step110, at least one tag 10 is detected at a subsurface location with asensor 60 disposed in the borehole. The tag 10 may be configured toprovide a distinguishable identifier via any conventional means as knownin the art and disclosed herein. At step 115, a signal associated withthe at least one detected tag 10 is conveyed along an interconnectedwired tubular 21. The signal may be conveyed solely along the wiredtubulars 21 or in combination with other telemetry assemblies as knownin the art and disclosed herein.

FIG. 5 shows a flow chart of another example downhole method 200 thatincludes, at step 205, disposing a plurality of interconnected wiredtubulars 21 within a borehole traversing a subsurface formation. At step210, at least one source/sensor 60 disposed in the borehole is activatedto detect a tag 10 at a subsurface location. The source/sensor 60 maycomprise any conventional sources or sensors as known in the art anddisclosed herein. The tag 10 may be configured to provide adistinguishable identifier via any conventional means as known in theart and disclosed herein. At step 215, a signal associated with the atleast one detected tag 10 is conveyed along an interconnected wiredtubular 21. The signal may be conveyed solely along the wired tubulars21 or in combination with other telemetry assemblies as known in the artand disclosed herein.

It will be apparent to those skilled in the art that aspects of theinvention may be implemented using one or more suitable general-purposecomputers having appropriate hardware and programmed to perform thetechniques disclosed herein. The programming may be accomplished throughthe use of one or more program storage devices readable by the computerprocessor and encoding one or more programs of instructions executableby the computer for performing the operations described above. Theprogram storage device may take the form of, e.g., one or more floppydisks; a CD ROM or other optical disk; a magnetic tape; a read-onlymemory chip (ROM); and other forms of the kind well known in the art orsubsequently developed. The program of instructions may be “objectcode,” i.e., in binary form that is executable more-or-less directly bythe computer; in “source code” that requires compilation orinterpretation before execution; or in some intermediate form such aspartially compiled code. The precise forms of the program storage deviceand of the encoding of instructions are immaterial here. Thus theseprocessing means may be implemented in the surface equipment, in thesystem tools, in a location remote from the well site (not shown), orshared by these means as known in the art. Aspects of the invention mayalso be implemented using conventional display means situated as desiredto display processed or raw data/images as known in the art.

The above disclosed examples include interconnected wired tubulars, orwired drill pipe, as a telemetry method. This is only provided as anexample. Those having ordinary skill in the art will realize that one ormore of the advantages of the disclosed examples may be achieved throughthe use of other telemetry methods known in the art. Such othertelemetry methods include mud-pulse telemetry, electromagnetictelemetry, and acoustic telemetry, among others.

While the present disclosure describes specific aspects of theinvention, numerous modifications and variations will become apparent tothose skilled in the art after studying the disclosure, including use ofequivalent functional and/or structural substitutes for elementsdescribed herein. For example, it will be appreciated that the tools andsystems comprising the disclosed aspects of the invention may beimplemented for use in various subsurface operations (e.g., whiletripping, while casing, etc.). All such similar variations apparent tothose skilled in the art are deemed to be within the scope of theinvention as defined by the appended claims.

1. A downhole system, comprising: at least one tag configured to providea distinguishable identifier and set for selective release to asubsurface location; and at least one sensor disposed on a drill stringcomprising a plurality of interconnected drill pipes, wherein the atleast one sensor detects the at least one tag at a subsurface location,and further wherein the at least one sensor is configured to transmit asignal associated with the at least one tag to a surface location. 2.The system of claim 1, wherein the at least one tag is set for selectiverelease from a surface location for transit to the subsurface location.3. The system of claim 1, wherein the at least one tag is set forselective release from a tool disposed subsurface.
 4. The system ofclaim 1, wherein the at least a portion of the drill string comprises aplurality of interconnected wired tubulars.
 5. The system of claim 1,comprising a plurality of sensors disposed on the drill string andconfigured to detect the at least one tag.
 6. The system of claim 1,further comprising a processor configured to alter operation of asurface or subsurface component based on detection of the at least onetag at the surface location or the subsurface location.
 7. The system ofclaim 1, further comprising a processor configured to activate releaseof the at least one tag to the subsurface location.
 8. The system ofclaim 1, further comprising a detection unit to detect the at least onetag at the surface location.
 9. The system of claim 1, wherein a portionof the drill string comprises interconnected wired tubulars, and whereinthe at least one sensor is configured to transmit a signal associatedwith the at least one via the interconnected wired tubulars.
 10. Amethod, comprising: detecting the at least one tag at a subsurfacelocation with a sensor disposed on a drill string, the tag configured toprovide a distinguishable identifier; and conveying a signal associatedwith the at least one tag from the sensor to a surface location.
 11. Themethod of claim 10, wherein at least a portion of the drill stingcomprises an interconnected wired tubular string.
 12. The method ofclaim 10, further comprising releasing the at least one tag from asurface location.
 13. The method of claim 10, further comprisingreleasing the at least one tag from a tool disposed subsurface.
 14. Themethod of claim 10, further comprising using the at least one tag to doat least one of determine a fluid flow property, determine a kicklocation, determine an event location, determine a depth location,determine a transit time, monitor cement placement, monitor gravelpacking, convey information, and determine a cuttings flow.
 15. Themethod of claim 10, further comprising adding the least one tag to afluid for disposal subsurface.
 16. The method of claim 13, furthercomprising determining a time between the step of releasing the at leastone tag and the step of the detecting the at least one tag.
 17. Themethod of claim 10, further comprising activating a plurality of sensorsdisposed in the borehole to detect the at least one tag.
 18. The methodof claim 10, further comprising altering operation of a surface orsubsurface component based on detection of the at least one tag at asurface or subsurface location.
 19. The method of claim 13, furthercomprising automatically activating the step of releasing the at leastone tag in the borehole.
 20. The method of claim 10, further comprisingdetecting the at least one tag at a surface location.
 21. A method,comprising: positioning a plurality of sensors on an interconnectedwired tubular to detect a location of a tag, wherein the tag has adistinguishable identifier; and conveying a signal associated with thetag from the plurality of sensors along interconnected wired tubular.22. The method of claim 21, further comprising releasing the tag in aborehole and detecting the tag in the borehole, and further comprisingdetermining a time between the releasing and the detecting the tag. 23.The method of claim 21, further comprising using the tag to do at leastone of determine a fluid flow property, determine a kick location,determine an event location, determine a depth location, determine atransit time, monitor cement placement, monitor gravel packing, conveyinformation, and determine a cuttings flow.
 24. The method of claim 21,further comprising altering operation of a surface or subsurfacecomponent based on detection of the tag.
 25. The method of claim 21,wherein the signal comprises a time the tag is detected by one of theplurality of sensors.